Fair Value Measurements (Details 1) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
FES | Debt Securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	$ 1,023	$ 980
Unrealized Gains	26	13
Unrealized Losses	0	0
Fair Value	1,049	993
FES | Equity Securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	90	0
Unrealized Gains	6	0
Unrealized Losses	0	0
Fair Value	96	0
OE | Debt Securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	128	123
Unrealized Gains	3	1
Unrealized Losses	0	0
Fair Value	131	124
TE | Debt Securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	52	42
Unrealized Gains	1	0
Unrealized Losses	0	0
Fair Value	53	42
TE | Equity Securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	24	0
Unrealized Gains	2	0
Unrealized Losses	0	0
Fair Value	26	0
JCP&L | Debt Securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	353	281
Unrealized Gains	9	9
Unrealized Losses	0	0
Fair Value	362	290
JCP&L | Equity Securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	21	80
Unrealized Gains	1	17
Unrealized Losses	0	0
Fair Value	22	97
Met-Ed | Debt Securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	249	127
Unrealized Gains	5	4
Unrealized Losses	0	0
Fair Value	254	131
Met-Ed | Equity Securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	32	125
Unrealized Gains	1	35
Unrealized Losses	0	0
Fair Value	33	160
Penelec | Debt Securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	210	145
Unrealized Gains	4	4
Unrealized Losses	0	0
Fair Value	214	149
Penelec | Equity Securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	20	63
Unrealized Gains	1	16
Unrealized Losses	0	0
Fair Value	21	79
Debt Securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	2,015	1,699
Unrealized Gains	48	31
Unrealized Losses	0	0
Fair Value	2,063	1,730
Equity Securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	187	268
Unrealized Gains	11	69
Unrealized Losses	0	0
Fair Value	$ 198	$ 337